BP said the 4-inch tube is working, siphoning 84,000 gallons a day to a ship, oil that would otherwise have dumped into gulf waters. But oil continues to bleed into new areas, and experts fear it could wind its way up the East Coast.

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Oil Spill: New Leak Video and Tar Balls

About 46,000 square miles in the gulf are now off limits to fisherman. In parts of the gulf, the oil has been seen breaching the booms put out to contain it.

But officials have determined that tar balls found in Florida are unconnected to the BP spill.

Some experts agree with BP that the insertion tube has made significant headway in controlling the spill.

"The riser insertion tube can only siphon off a certain amount of the oil, which is probably about 30 to 40 percent of the oil that's coming out of the tube," Rice University professor of civil and mechanical engineering Satish Nagarajaiah said. "I think it's good progress."

But others, including residents who depend on the ocean for their livelihoods, say it's not good enough. Some who rely on Florida's $60 billion a year tourism industry say the damage may already be done.

"We know of people who're saying they're not coming in June because of the oil," said Spencer Slate, who owns a dive center in Key Largo. "Nothing functions down here without tourism."

The 60 tar balls found in Key West range in size from 3 to 8 inches in diameter, according to the U.S. Coast Guard. But National Oceanic and Atmospheric Administration officials said Tuesday that they believe the diluted oil carried by the current would pose a minimal risk to Florida and the East Coast.

Congress and White House Examine Government Response

In Louisiana, Republican Gov. Bobby Jindal completed a flyover of the Plaquemines Parish and found troubling signs of a growing ecological problem.

Deep in Louisiana's weblands near Pass a Loutre, Jindal said he saw heavy oil that could cause major damage to aquatic life and the seafood industry.

"This is the first time we've seen this much heavy oil this far into our wetlands," Jindal said at a press conference following the flyover, noting that more heavy oil is forecast to hit the wetlands in the coming days.

Government officials Tuesday recapped the impact of the spill on wildlife so far. Thirty-five oiled birds have been discovered, 23 of which were brought in dead. One hundred and fifty-six sea turtles and 12 bottlenose dolphins have been found dead, though necropsies do not show any external or internal signs of oil.

"This spill is significant, and in all likelihood will affect wildlife for years if not decades," said Rowan Gold, the acting director of the U.S. Fish and Wildlife Service.

"I think that there is additional work that should have been done with respect to blowout prevention mechanisms," Salazar conceded.

In his first appearance before lawmakers since the drilling accident 29 days ago, the interior secretary promised to give officials who regulate offshore drilling "more tools, more resources, more independence and greater authority."

When asked whether another rig could have a similar problem, Salazar said that all rigs are inspected every 30 days, according to regulations.

But ABC's Jake Tapper reports that the requried monthly inspections do not always happen.

At the Deepwater Horizon site alone in the past five years, an entire year's worth of inspections did not happen. Of 60 required inspections, only 48 occurred, and that includes four missed inspections out of the 16 required since President Obama's inauguration.

That's evidence to some of a wider problem.

"It's plain that there's a long history here of a lax oversight role by the part of the Minerals Management Service," said Wesley Warren, Director of Programs for the Natural Resources Defense Council.

On Monday, one of the regulators who was charged with monitoring offshore oil programs in the gulf for more than a decade announced he would retire at the end of the month. Chris Oynes, associate administrator for the Minerals Management Service, is the first administration official to resign since the spill.